With the continuous improvement of people's living standard, pressure cooker gains increasing popularity among people for its convenient use, environmental protection and energy saving. In respect of the structure, it mainly comprises a shell, a cooker cover and a cooker body, wherein a float valve, a pressure relief valve and a safety valve are provided on the cooker cover; when the pressure in the cooker body rises to a certain level, the high pressure will prop up the float of the float valve to prevent the rotary opening of the cooker cover. It has a simple structure and is easy to use. The disadvantage of the structure is that the float can move up under external force whether the pressure in the cooker body is sufficient or whether the cooker cover is open, thus causing trouble to users.